1. Field of the Invention
The present invention relates to a tone hole pad which is mounted within a cup for opening or closing a tone hole of a musical wind instrument.
2. Description of the Prior Art
A conventional tone hole pad for a wind instrument is shown in FIGS. 11 to 15 and comprises a circular metal cup including a bottom portion and a wall portion formed on the periphery of the bottom portion. A screw receiver 33 is brazed to the bottom portion (FIG. 13) and a cushion pad 35 and an adjusting paper 36 are mounted therein. The cushion pad 35 is formed of a thick felt 39 backed by cardboard 40 and wrapped in a pad skin 41 and has a mounting hole 42 formed in the center thereof (FIG. 14). An adjusting paper 36 is first placed on the bottom portion of the cup, and the cushion pad 35 is then mounted thereon and fixed by a pad washer 37 and a bolt 38 (FIG. 15). The adjusting paper 36 may regulate the pad""s surface in order to contact with a tone hole rim 34 by increasing or decreasing the surface level. The cup 32 provided with the cushion pad and the adjusting paper is brazed to a lever 31 of a key mechanism provided on the outer surface of the tube body of the instrument.
One of the problems in the prior art tone hole pad is conformability of the cushion pad 35 with the tone hole rim 34 in that air leaks from a gap produced between the pad""s surface and the tone hole rim. The first reason for this is that the screw receiver 33 is liable to be obliquely brazed to the bottom portion of the cup 32. The oblique screw receiver makes the pad washer 37 unevenly press the cushion pad 35 against the bottom portion of the cup 32, and, accordingly, deteriorates the conformability of the cushion pad 35. In the process of manufacture, in fact, it is hard for a worker to braze such screw receiver 33 to the bottom portion of the cup 36 evenly, as it requires a skillful technique. The second reason is the uneven bottom portion of the cup 32. When the cushion pad 35 is pressed by the pad washer 37 against the uneven bottom portion of the cup, the cushion pad is then distorted, whereby a gap is produced between the pad""s surface and the tone hole""s surface, resulting in air leaking, even though the adjusting paper lies on the bottom portion of the cup.
A further problem is that tears in the cushion pad""s skin can eventually occur on the portion of the skin that covers the cushion pad. The tears are caused by the pad""s inability to maintain an even tension on the skin during repeated contact with the tone hole surface. Therefore, a pad assembly is needed having components that can provide the necessary support for the pad""s sealing surface and maintain an even tension on the pad""s skin. The deformation of the cushion pad caused by the uneven bottom portion of the cup as described in the previous paragraph is also a cause of tears in the cushion pad""s skin. Replacement of the pad assembly requires the installation of a new pad assembly and adjustment thereof to conform the cushion pad""s surface to the tone hole surface, which is both time consuming and expensive.
A further problem is that in the prior art tone hole pad, the cushion pad is fixed by a pad washer and bolt in the center. In other words, only central area of the cushion pad is pressed firmly against the bottom portion of the cup. Accordingly, the pressure of the pad washer is concentrated near the center of the pad so that the outer peripheral portion of the cushion pad is forced to float up and protrude out along an edge of the wall portion of the cup, causing distortion of the cushion pad, whereby the pad""s conformability deteriorates. Any measures to prevent the outer peripheral portion of the cushion pad""s surface from protruding out along the edge of the cup""s wall is awaited.
Accordingly, an object of this invention is to provide a tone hole pad for a musical wind instrument that has solved the problems inherent in the prior art conventional tone hole pad.
To achieve the above object, according to one aspect of this invention, there is provided a tone hole pad for a wind instrument comprising a circular metal cup brazed to a lever of a key mechanism provided on the outer surface of a tube body of a wind instrument. A bottom portion of the cup has an annular wall portion formed on the peripheral portion of the bottom portion. The annular wall portion has a lip which curves inward toward the center thereof to prevent a pad""s surface from floating. A circular metallic base is formed of a disk-shaped metal plate having a diameter substantially the same as the inside diameter of the wall portion of the cup and has a stem portion formed integrally therewith exactly perpendicular to the surface thereof, within which a female screw is formed. The circular metallic base is brazed to the bottom portion of the metal cup. The metallic base is also provided with a ring-shaped concave portion (or recess) formed on the peripheral portion of the upper surface thereof with an inside diameter smaller than a tone hole and an appropriate width and depth. A plurality of holes are formed at regular intervals between the central stem portion and the peripheral ring-shaped concave portion. A corner portion of the periphery of the rear surface of the metallic base is beveled to conform to a curved portion of an inner peripheral portion of the bottom portion of the cup.
A pad assembly is comprised of a felt body formed of a disk-shaped piece of felt the upper surface of which is coated with a resin film having the same diameter as that of the metallic base and a mounting hole formed in the center thereof, an elastic resin plate formed of a disk-shaped elastic resin plate having the same diameter as that of the felt body and a mounting hole formed in the center thereof, and a mount paper formed of disk-shaped cardboard having the same diameter as that of the felt body and a mounting hole formed in the center thereof, and a mount paper formed of disk-shaped cardboard having the same diameter as that of the felt body and a mounting hole formed in the center thereof. All of the felt body, the elastic resin plate and the mount paper are mounted on the metallic base in the order of the mount paper, the elastic resin plate and the felt body, from the bottom, and fixed by a pad washer and a bolt in the cup.
In accordance with the tone hole pad of the present invention, the following effects and advantages can be achieved.
First, in the process of manufacture, it is easier to settle the metallic base in a proper position in the bottom portion of the cup owing to the beveled portion formed on the peripheral portion of the rear surface thereof, covering the whole inside rounded portion of the bottom portion of the cup. When the metallic base is brazed to the bottom portion of the cup, a number of the holes perforated between the stem portion and the peripheral concave portion in the metallic base are also of use for a worker, through which he can observe with the eye the brazing work and condition in the other surface of the metallic base. This enhances the work efficiency and contributes to reducing weight.
As a result of this metallic base, a stem portion can be stabilized exactly perpendicular to and in the center of the bottom portion of the cup. Accordingly, the pad assembly can be pressed by a pad washer evenly and uniformly so as to maintain its surface exactly parallel to the tone hole surface to avoid any risk of damage to the pad surface which might cause a gap between the pad""s surface and the tone hole. Accordingly, complete conformability of the pad""s surface with the tone hole can be ensured.
As comprised of the felt body formed of a thin piece of felt, the upper surface of which is coated with a resin film, the elastic resin plate and the mount paper, the pad assembly itself is elastically deformable and restorable, so that the pad""s surface does not suffer from excessive pressure from the tone hole by a player""s strong touch or uneven pressure by distortion of the tone hole. In addition, the mount paper deflects into the space portion formed in the ring-shaped concave portion on the peripheral portion of the upper surface of the metallic base, so that the shock caused when the tone hole is closed is alleviated.